Shock resisting steering mechanism



Jan. 17, 1939; M. w. GIESKIENG SHOCK RESISTING STEERING MECHANISM Filed March 12, 1938 I INVENTOR MAR/0N W G'IESK/ENG ATTORNEY Patented Jan. 17, 1939 UNITED STATES PATENT OFFICE shook sesame STEERINGMECHANISM v Denver, 0016." i Application Marc 2;, 1938, serial'No. 195,638

t (oi. i4- -500 This invention relates to improvements in Figure l is a longitudinal section through the steering gears for automobiles and has reference steering column;

more particularly to a steering" gearthat will 1' FigurejZ is'an enlarged sectional detail; prevent shocks from being transmitted from the Figure 3 is a section taken on line 3-3 Fig.. 2 v wheels to the steering wheel-. 5 and shows the teeth in spaced position;. 7 5

The ordinary steerin-g gear comprises a' ste'er- Figure, 4 is a section, similar to t" at shown in ing post having a steering wheel at one end anda Fig. 3 andshows the teeth in operative position; worm at the other end.' Aworm wheel 'is' oper- I Figure 5 is a vector diagram showing the rela-patively associated with the worm andoscillates a tionshipof the forces when the parts have moved 7 steering lever or crank' arm thatyis connected in response toiorces produced by shock; and g 10 with the drag link of the steering gear; Figure 6 is a diagram, similar toithat shown Inspite of the worm driveit has been-found in Fig. 5 but modified by a force applied to the that shocks are transmitted from thewheels; to steering wheel. the steering wheel, often with sufiicientseverity In thedrawing reference numeral 5 denotes the to cause the driver to lose control of the car with steering shaft which is usually enclosed in a tube 15 the result that serious accidents occur-. 1; 6. A steering Wheel. 7 is attached to the upper I am aware that it has been proposed to mount end of the steering; post. The lower end of the the worm on the steering post in such- 'ajway steering post is'journaledin suitable bearings 8 that it can slide along but not-rotate thereon; andllthat. are located ina casing I0 having an the worm being held inneutral position integral attaching member H for securing it to 20 springs. However, such an arrangementialone i's an automobile frame. The attaching, member not sutficient, first because it permits the front has a'cover which has not been shown and has wheels to turn so far in response to severe shocks a recess [2 in which the worm wheel i3 is posithat accidents occurfrom this cause alone and tioned. The wall of the recess has stops I I that unless the longitudinal movement is suificient to limit the rotation of the worm wheel, which is 25 absorb the shocks these will stillib transmitted secured to a shaft I? that projects through the to the steering wheel. 1 5 wall of the recess and carries a steeringlever or It is the object of this invention to producea a ne, whose outer end is connected to the, drag steering mechanism of the-general type described link 11 by a ball and socket joint l8, p a which will p s t y tch t e wo against f'casing'f In has a cylindrical opening I9 that 0 rotary movement due to shock forces transmitted terminates in a shoulder 20, which is provided to it from the front wheels ofan automobile with a plurality of teeth 2i. 7 From the shoulder through the worm gear. f 20 a cylindrical opening 22 ofismaller diameter The invention briefly tlf p f sj a than opening) extendsf to the flange '23" that steering mechanism having a steering'post t0 servesas an abutment'ior the thrust bearing 8- 3 which a worm is attached in suoh'away it that i positioned in the cylindrical recess 24. can move longitudinally bu not tatably em- The upper end of casinglll has aithreaded sec on. Springs retain the worm in neutral position ti n '25 of r d c d diameter t whi h the'cap 26 during normal operation but permitit to move is threadedi Thefltube 6 is inserted in an opena longitudinally in response to wheel shocks-(The ing incap 26 in the manner shown, 7 V 0' hear in Which the Steering p st is mounted The inner surface of opening 19 has a threaded has a number of teeth at each end of he w section-21 at its lower end to whichrthe bottom and facing the latter; The ends of the worm arens re or cap 23 is attached, Ca 28 has a, provided with teeth that will interlock with the cylindrical-recess 29 in which is positioned the teeth on the bearing when the worm moves longibearing 9 and has an opening 30 for ther eceptudinally in the steering post and thus positively tion of the lower end- 3! ofth t g' h 5; latching it against both rotary andlongitudinal Shaft 5 has a, cylindrical section 32 bli whi hth movement whereby the transmissionsof severe worm 33 is carried Splines 34 holdthe worm shocks to the drivers hands is preventedll a from rotating on the shaft but permit it to move Having thus briefly described the invention, longitudinally thereon s l the same will now be described indetail and for It will be observed that the worm i rovided t purpose reference will be hadgtothe'accom at its ends with flanges 35 that form a snug fit panying drawing iniwhich the invention has been with opening l9 and these flanges are provided illustrated in one specific embodiment and with teeth SB'that are adapted to interlock with hich: H i. a. teeth 2| onshoulder 20 and withsi'milar teethon the inner end of the cylindrical portion 31 of cap 28. Helical coil springs 38 extend from the ends of the worms to flange 23 and shoulder 39.

The coil springs are quite powerful and are under comparatively small compressive strains when the worm is in neutral position. If the worm gear 45 exerts an unusual force on the worm which tends to move it in the direction of its length, it will compress one or the other of springs 38 sufiiciently tobring the teeth 36 on the flanges into overlapping engagement the corresponding set of teeth 2l'. The force exerted by the worm wheel is resolved into two components, one of which tends to move the worm longitudinally and the other of which tends to rotate it. The rotary component varies with the pitch of the worm and is quite negligible'for movement of the worm and steering shaft is pre- 1 vented by the interlockingof teeth 36 with teeth 'course of the automobile.

It will be observed that teeth 2] and 36 a're'in clined in both directions. When the force exerted on the worm by the worm wheel is sufiilem to move the teeth into engagement it will hold them in engagement so that they cannot slip even if the engaging surfaces are inclined.

In Figs. 5 and 6, force diagrams have been shown in which the vertical angles or the teeth are 90 degrees. Line 0A represents the value of the force exerted on the worm tending to move it longitudinally and OB represents the value of the rotary component due to the pitch angle of the worm teeth. Line OB is short in comparison with line OA and the angle 20 is therefore quite small.

acute angle and there is therefore no tendency for the teeth to slip. I 7

"If the operator exert a turning force on the steering Wheel in a. direction to increase line OB to OB angle 10 will begin to increase and as soon as this exceeds 45' degrees angle a becomes obtuse and the gears tend to'slip. The operator is there'- fore always in position to guide the'automobile. As soon as the longitudinal component OA de creases sufficiently to be overcome by the action or the spring compressed thereby the worm will immediately return to neutral position.

' Persons that do a large amount of driving, especially those who make long trips, are agreed that one of the greatest causes contributing to fatigue is the tension or strain due to the necessity of constantly maintaining a firm'grip on the steering wheel for fear that some sudden shock will cause it to be rotated and thus change the When the present safety device is employed the drivers may relax because of the knowledge that even if some sudden road shock should be transmitted from the front wheels to the steering mechanism the latter will automatically latch until the force of the shock has passe 7 Although the angle of the teeth has been illustrated as approximately 90 degrees, it is probable that a larger angle would be preferable and the intention is to selectthe most suitable angle;

When the recess 12 is closed by the covef'r'nember, not shown, the whole interior forms ,a closed chamber that may contain oil. It will be ob-.

served-that flanges 35 act as pistons or plungers.

It will be observed that whenthe v angle of the teeth is 90 degrees, angle a. is an and when the spring chambers are full of oil we obtain a dash pot action. The spring chambers may be connected by a by-pass 40 having a valve 4|.

Oil or grease is introduced through opening 43, normally closed by a screw plug.

It will be apparent from the above that by the slight change described above an ordinary steering mechanism can be made non-reversing so as to prevent shocks from being transmitted to thesteering wheel and-the danger of accident resulting from the driver losing control of the automobile is therefore greatly reduced.

Having described the invention what is claimed ias'new is: a 1, A steering gear for automobiles comprising, in'combination, a steering post having its upper end provided with a steering wheel, a casing enclosing the lower end of the steering post, spaced bearings in the casing, a worm slidably but nongotatably carried by the post, within the casing, compression springs encircling the post, the ends of the springs engaging shoulders formed within the casing and the ends of the worm, the end walls of the casing having a plurality of teeth facingthe ends of the worm and normally spaced therefrom, the worm'having an annular row of teeth on each end positioned to engage the teeth on the casing end walls, a worm gear pivotally connected to the casing and operatively associated with the worm, and means comprising a portion of the steering gear for exerting a rotary force on the worm gear to move the worm longitudinally on the steering post, to bring the teeth on the worm into engagement with the teeth on the casing; end walls. v

V 2. A shock resisting steering gear comprising, in combination, a' steering post having one end provided with a steering wheel, the other end having a worm mounted thereon for limited longiti dinal movement, means for. holding the worm from rotating on the steering post, a casing enclosing the worm, the casing havingspaced bearings for the steering post, the worm being positionedbetween the bearings, a worm wheel pivotedon the casingand operatively associated with the worm, two helical compressionsprings encircling the. post, one at each end of the worm, for resisting longitudinal movement of the worm in either direction, two sets'of teeth carried by the casing, one at each end of the worm and Spaced from the latter when it is in normal position, each end of the worm having an annular row of teethpositioned to engage the corresponding set of teeth'on the casing, when the worm is moved longitudinally against the action of either spring. V

3. A shock resisting steering gear comprising, in combination, a, steering post having one end provided with a steering wheel, the other end having-a worm mounted thereon for limited longi tudinal movement, means for holding the worm from rotating on the steering post, a casing enclosingthelworm', spaced bearings for the post, the worm being positioned between the bearings, a; worm wheel, pivoted on the casing and operatively associated with the worm, a helical compression spring at each end of the worm, encircling the steering post. between the worm and the adjacentbearing, for resisting longitudinal movement of the worm in either direction,- two sets of teeth carriedby the casing, one at each end of the worm and: spaced from the latter when it is in normal; position, the sides of the teeth being inclined in opposite directions, each end of the worm having an annular row of correspondingly shaped teeth positioned to engage the corresponding set of teeth on the casing, when the worm is moved longitudinally on the post.

4. In a steering mechanism having a casing, for the reception of a steering post or shaft, provided at one end with a steering wheel and at the other with a worm, slidably but non-rotatably attached thereto, a worm gear pivoted to the casing and operatively connected with the worm for rotation thereby, compression springs encircling the post at each end of the worm, with one end inengagement therewith the other ends engaging a shoulder formed within the casing, the springs serving to hold the worm in a predetermined neutral position, the end walls of the casing having each a set of teeth spaced from the ends of the worm when the latter is in neutral position, the ends of the worm having each an annular row of teeth for engaging the teeth on the casing when the worm is moved longitudinally from normal position.

MARION W. GIESKIENG. 

